Abdominal Enhanced Computed Tomography Image by Artificial Intelligence Algorithm in the Diagnosis of Abdominal Aortic Aneurysm

The purpose of this study was to investigate the clinical value of CT angiography (CTA) images processed by the segmentation denoising technique based on deep convolution neural network algorithm in the diagnosis of abdominal aortic aneurysm (AAA) and the detection of disease changes. A total of 98 patients with ruptured AAA were retrospectively selected as the study subjects. Patients were grouped according to whether the CTA images were optimized, the images receiving artificial intelligence segmentation and denoising were set as the observation group, and the CTA images without optimization were set as the control group. The detection and diagnosis effects of CTA images before and after the treatment were compared. The surgical results were used as the standard to analyze the diagnostic effect, and the maximum diameter measurement results of AAA and the proportion results of intraluminal thrombus (ILT) were compared. Although the sensitivity and accuracy of diagnosis in the observation group (97.73% and 94.9%) were higher than those in the control group (95.45% and 92.86%), there was no significant statistical significance ( P > 0.05 ). When the diameter of AAA was no less than 5 cm, all results showed that the coverage percentage of intraluminal thrombus (ILT) was over 50%. When the diameter of AAA was less than 5 cm, only 55.56% of the results showed that the percentage of ILT coverage was over 50%, with considerable differences ( P > 0.05 ). According to the results of the study, it was found that there was a certain relationship between the thrombus coverage of the abdominal aortic wall and the growth rate of AAA. The deep convolution neural network algorithm had a certain effect on the treatment of CTA, but it is not obvious. However, CTA had a better clinical diagnostic effect on AAA.

P.064 Physician Approaches to Imaging and Revascularization for Acutely Symptomatic Carotid Stenosis: Insights from the Hot Carotid Qualitative Study

Background: Evidence informing the choice between endarterectomy and stenting for acutely symptomatic carotid stenosis (“hot carotid”) is dated, and uncertainties remain regarding the optimal imaging modality. We sought to explore the thoughts of stroke physicians regarding the perioperative management of patients with acute symptomatic carotid stenosis. Methods: We conducted semi-structured interviews regarding “hot carotid” management with purposive sampling of 20 stroke physicians from 14 centres in North America, Europe, Asia, and Australia. We identified key themes using conventional qualitative content analysis. Results: Timely imaging availability, breadth of information gained, and surgeon/interventionalist preference emerged as important themes informing the choice of imaging modality. Multidisciplinary decision making, operating room/angiography suite availability, and implications of patient age and infarct size were important themes related to the choice of revascularization. Areas of uncertainty included utility of carotid plaque imaging, timing of revascularization, and the role of intervention with borderline stenosis or intraluminal thrombus. Conclusions: Our qualitative analysis revealed themes that were important to stroke experts. Teams designing international trials will have to accommodate identified variations in practice patterns and take into consideration areas of uncertainty, such as timing of revascularization, imaging of carotid plaque and non-stenotic features of carotid disease (intraluminal thrombus, plaque morphology).

Abstract 1122‐000038: Anticoagulation Versus Antiplatelet Alone in Acutely Symptomatic Carotid Artery Stenosis

Introduction : Acutely symptomatic carotid artery stenoses carry a significant risk of early ischemic recurrence. Timely initiation of effective antithrombotic therapy and revascularization interventions are necessary to reduce the risk of recurrent events. While antiplatelet agents are widely used, there is some limited evidence supporting short term anticoagulation as well. Moreover, most patients require early revascularization with carotid endarterectomy (CEA) which is almost exclusively performed with anticoagulant protection. Thus, we sought to determine the potential safety and efficacy of short term pre‐operative anticoagulation in the secondary prevention of stroke/TIA from acutely symptomatic carotid stenosis. Methods : A prospective single institution registry of carotid revascularization was queried retrospectively. We included all CEA patients who presented to the hospital with acute ischemic strokes or TIAs attributed to the ipsilateral stenotic lesion of the internal carotid artery. Treatment arms were assigned based on exclusive use of antiplatelet agents (AP) or use of anticoagulant (AC) with or without additional antiplatelet agents. Results : 443 patients were identified; 342 treated with anticoagulation (97.7 % IV Heparin) and 101 with antiplatelets alone (95.1% aspirin, 23.8% clopidogrel and 24.8% aspirin and clopidogrel). Baseline characteristics for the antiplatelet and anticoagulation groups were similar except for mean age (73±9.5 vs 71±10.5), premorbid mRS (1.4±1.3 vs 1.0±1.2) and stroke as presenting symptom (53.5 vs 65.8%). Notably the stroke severity (admission NIHSS), degree of stenosis, presence of intraluminal thrombus or median time to surgery was balanced between treatment arms. Patients treated with anticoagulation had significantly lower incidence of recurrent TIA/Stroke (10.9 vs 3.8%, p = 0.006). Symptomatic ICH was only observed in 1 patient in the AC arm and none of the AP group and postoperative bleeding was similar (2 vs 2.3%, p = 0.83). AC appeared to be protective with OR 0.30 (p = 0.007) for incidence of the primary outcome when controlling for degree of stenosis, presence of intraluminal thrombus, stroke severity, premorbid mRS, age, gender and time to surgery. Conclusions : Our findings suggest short term pre‐operative anticoagulation in patients with acutely symptomatic carotid stenosis awaiting revascularization is a potentially safe and effective alternative to antiplatelet agents alone. Confirmatory prospective studies are warranted.

Does the Intraluminal Thrombus Provoke the Rupture of the Abdominal Aortic Aneurysm Wall?

The role of intraluminal thrombus (ILT) in the rupture of abdominal aortic aneurysms (AAA) is controversial, and it is unclear whether it increases or decreases the risk of rupture. This research aims to find a clear answer to this question. Previous computer modelling suggests that an ILT lowers oxygen dissemination to the AAA wall, contributing to wall thinning. The methodology used in this study determines the amount of oxygen reaching the aneurysm wall after passing through the ILT by using the porous nature of the ILT to recreate the condition as closely as feasible. Using computed tomographic images, patient-specific three-dimensional (3D) AAA geometries were recreated. Modelling blood and oxygen flow in AAA was obtained using a computational fluid dynamics (CFD) approach. Our findings indicated that the oxygen volume percentage had completely reached the aneurysm wall. Only at the inlet and outflow did the greatest wall shear stress (WSS) occur, with a significant drop in the central region of the aneurysm wall. CFD was used to calculate the velocity, pressure, and WSS of aortic blood flow. ILT had no effect on oxygen flow to the aneurysm wall, disproving the theory that it produces local hypoxia.

Intracranial non-occlusive intraluminal thrombus may indicate underlying etiology of large vessel occlusion in patients undergoing endovascular therapy

BackgroundThe underlying etiology of intracranial non-occlusive intraluminal thrombus (iNOT) remains unknown. This study aimed to investigate whether the presence of iNOT can indicate the underlying etiology of large vessel occlusion (LVO) in patients undergoing endovascular therapy (EVT).MethodsAmong patients who underwent EVT at three comprehensive stroke centers, we included those with intracranial LVO in the anterior circulation. The presence of iNOT was determined by pretreatment DSA. We investigated the association between iNOT and intracranial atherosclerotic stenosis (ICAS) related LVO.ResultsOf 546 patients, 44 (8.1%) had iNOT. Patients with iNOT were younger, had less hypertension, atrial fibrillation, and a history of antiplatelet use. In addition, the involvement of the M1 segment of the middle cerebral artery (MCA) was more frequent. However, they had a lower National Institutes of Health Stroke Scale (NIHSS) score on admission and longer onset to recanalization time compared with patients with no iNOT. In a logistic regression model adjusting for age, sex, atrial fibrillation, smoking, prior antiplatelet and anticoagulant use, intravenous tissue plasminogen activator, NIHSS on admission, number of technical trials, intraprocedural re-occlusion, and the location of LVO (p<0.10 in the univariate analysis), the presence of iNOT was significantly associated with ICAS related LVO (adjusted OR 3.04; 95% CI 1.33 to 6.90; p=0.007).ConclusionsThe presence of iNOT may reflect an underlying ICAS related LVO in patients undergoing EVT.

Heparin for Vertebral Intraluminal Thrombus Causing Retroperitoneal Hemorrhage from Occult Renal Angiomyolipoma

Stroke is a common cause of mortality and serious long-term disability worldwide. In the acute setting, current American Heart Association/American Stroke Association guidelines do not recommend routine anticoagulation for the management of acute ischemic strokes. However, short-term use of unfractionated heparin (UFH) in select subpopulations has demonstrated improved outcomes. While tools such as CHADSVASC and HASBLED scores are useful in stratifying risk of long-term anticoagulation in patients with nonvalvular atrial fibrillation and additional risk factors, the carefully selected patient populations for the design of these studies do not account for risk of hemorrhage from other preexisting conditions. Here, we present a patient with a posterior circulation intraluminal thrombus treated with UFH, who manifested with a near-fatal intra-abdominal hemorrhage from a previously undetected renal angiomyolipoma (AML).